1. The Field of the Invention
The present invention relates generally to the repair of cerebrospinal fluid leaks and reconstruction of anatomy from defects, and more particularly, from leaks which may result from a region of incompetence in the dura mater or cranial vault.
2. The Relevant Technology
Recent advances in endoscopic sinus surgery as well as traditional skull base approaches have produced an increasing number of CSF leaks following surgery. Acute or chronic CSF leaks have significant associated morbidity, including meningitis, pneumocephalus, intracranial hypotension, brain abscesses and seizures. More and more oncologic skull base surgeries are performed via a transnasal endoscopic approach, resulting in significant rate of CSF leaks. In addition, unintentional craniofacial trauma and transcranial skull base surgery can result in CSF leaks. Finally, in select patients, no identifiable etiology is found (idiopathic).
Traditionally, transcranial approaches were used to repair CSF leaks. This approached involved a craniotomy, brain retraction, and dural patch and some type of fibrin seal. More recently, in an attempt to limit morbidity, transnasal endoscopic techniques have been successful in repairing select skull base CSF fistulas. During an endoscopic repair, either abdominal fat or fascia lata from the thigh are most commonly used as grafting material to occlude the dural defect. Other materials include, pericardium, mucoperichondrium, middle turbinate bone as well as a variety of vascularized mucoperiosteal flaps. These materials are used for obliteration, an overlay graft or an underlay graft. Obliteration of the sphenoid sinus can be performed with any of the listed grafting materials. In an underlay technique, the grafting material is inserted a few millimeters intradural between the dura and the bone on all sides of the defect. Less successful is the overlay technique, where the grafting material is simply placed over the dural or bone defect and secured typically with fibrin glue. In conjunction, a variety of materials are used in conjunction with the grafting material and include fibrin glue, an absorbable gelatin sponge (Gelfoam) and an absorbable knitted fabric (Surgicel). In addition, a lumbar drain is typically inserted and kept in place to divert CSF for 3-7 days, depending on the
The techniques described above, for repair of CSF leaks, can be unreliable, require a second incision to harvest grafting material and commonly necessitate the use of a lumbar drain. Lumbar drains are typically used for 3-7 days and inserted at a distant site (lumbar) through a separate stab incision. They may be highly problematic, requiring frequent position changes of the catheter. There may also be at high risk of dislodgement and unintentional removal. When a patient has a lumbar drain in place, frequent monitor of the neurological status is required from the nursing staff. This may significantly increase the length and cost of the hospital stay following endoscopic surgery and is associated with potential complications including headaches, meningitis, intracranial hypotension, chronic CSF leaks and spinal abscess. Patients poorly tolerate this invasive post-operative procedure for CSF diversion.
As the above described techniques illustrate, the existing systems and procedures for repairing CSF leaks may not be as effective as desired.